Describes how clay minerals swell when exposed to water, effectively sealing any remaining pores and creating an impermeable barrier known as a shale seal.
Learn MotionWhy Oceans Don't Drain Into the Ground
Permeability and Porosity: The Key Barriers
The Role of Clay and Shale
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Finally, consider the soft stuff on top. Many ocean sediments are made of clay. When clay gets wet, its microscopic plates absorb water and swell up, like a sponge expanding. This swelling physically jams the tiny gaps between grains. Over millions of years, this compacted clay turns into shale, which is incredibly impermeable. It acts like a natural waterproof blanket, sealing the ocean floor and keeping the water where it belongs.
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